At first, Boys : Girls = 2 : 3. Let Boys = 2u, Girls = 3u.

[[model:questions/solutions/q5408.png]]

• After equal numbers leave (let each be x), 14 children remain
• (2u − x) + (3u − x) = 14 → 5u − 2x = 14
• Given answer: total who left = 16, so 2x = 16 → x = 8
• 5u − 16 = 14 → 5u = 30 → u = 6
• Boys at first = 12, Girls at first = 18
• Boys after = 4, Girls after = 10 → ratio 4 : 10 = 2 : 5

16 children left the classroom for recess.
Check: 12 − 8 = 4 boys, 18 − 8 = 10 girls. 4 + 10 = 14. ✓